1. Field of the Invention
This invention relates to traffic-rated covers for underground utility vaults and more specifically those traffic-rated covers that are spring-loaded to “pop-up” or spring open upon the release of a latching mechanism or locking mechanism of the cover.
2. Description of Related Art
A utility vault is an underground room providing access to subterranean public utility equipment, such as valves or other flow control devices for drinking water, drainage water, sewage, natural gas, or steam distribution networks, or switches, routers, or other electronic equipment for electric, telecommunications, television, or internet distribution networks. Utility vaults are similar to mechanical or electrical rooms in design and content. Utility vaults are located underground for aesthetic, safety, and security reasons. Typically, utility delivery networks include a series of main lines connected to branch lines that provide utility connections to individual houses and apartments. There could be a utility vault located at every junction between main lines and every junction between main line and branch line and at every junction between branch lines. Utility vaults are required with most sewer and drainage storage tanks, flow junctions, pump houses, and other areas of the sewage and drainage system of a village, municipality, town, city, or county. Thus, a typical utility distribution network or system includes a large number of utility vaults. Utility vaults are commonly constructed out of reinforced concrete boxes, poured cement, or brick. Utility vaults are typically entered through a manhole or vault cover on the upper surface or ceiling of the utility vault. Utility vault covers are used to prevent accidental and unauthorized access to a utility vault. Utility vault covers typically have latching and/or locking mechanisms to prevent unauthorized access to the utility vault.
A utility vault is typically a rectangular or square cuboid or box-shaped room. The utility vault cover is typically on the upper face of the cuboid. A utility vault cover is typically rectangle or square-shaped. A utility vault cover typically has one or two doors or hatches pivotally attached at one end to the upper face of the cuboid. A hatch is typically rotated upward to open the cover and gain access to the utility vault and pivotally rotated downward to close the cover and eliminate access to the utility vault.
A utility vault cover typically comprises a frame and a hatch. The frame is a closed-perimetered rigid assembly with an open center that is typically rectangular-shaped or square-shaped to fit the specific cuboid dimensions of the utility vault. The frame is attached to the utility vault on the upper face or at the upper edges of the vertical faces of the cuboid. The frame and utility vault are typically embedded into the ground with the upper surface of the frame generally flush with the upper surface of the ground of the surrounding area, which is typically earth, concrete, asphalt, or similar.
The hatch is a rigid planar member sized to fit and cover the upper face of the cuboid-shaped utility vault and to marry with the frame to make a semi-weather-tight connection with the frame. The hatch is typically square or rectangular shaped. One edge of the hatch is pivotally mounted on one leg of the frame so that the edge of the hatch opposite the pivotally mounted edge may be lifted upward to open the hatch and pushed downward to close the hatch.
As stated, utility vaults are located underground, and, as a result, a traffic-rated utility vault cover must be sturdy enough to support pedestrian traffic and vehicular traffic passing over top of it without losing structural integrity, deflecting, or bending. A traffic-rated utility vault cover must be of a very heavy-duty design to support the enormous amounts of weight of the people, cars, and trucks that may pass over the utility vault. As a result, a traffic-rated utility vault cover is typically extremely heavy and as a result is extremely difficult for crews and workers to open and close.
To combat the heavy weight issue, traffic-rated utility vault covers may further comprise one or more lift mechanisms or pop-up mechanisms that function to lift and open the hatch partially and substantially help crews and workers open and close the hatch in order to gain access to the utility vault. Pop-up mechanisms provide an upward torque force to push and rotate the hatch upward and hold it open by a certain gap, typically about 12 inches, after the utility vault cover latch has been released and/or the lock has been unlocked. Thus, after the latch and/or lock of the utility vault cover have been disengaged, the pop-up mechanism becomes free to push and lift the hatch rotationally upward and hold it partially open at an acute angle with respect to the frame. The acute angle results in an open gap of typically about 12 inches.
This gap allows the worker to more easily grab hold of the hatch and lift it completely open by rotating it upward to an obtuse angle with respect to the frame to provide full clearance for the worker to enter the utility vault through the open frame. The pop-up gap should be set at the distance that is just enough to reduce the leverage force required to open the hatch to a quantity that is capable of being exerted by one typical worker. As the pop-up gap increases, weight from the heavy hatch is transferred to the hinges, making the hatch seem lighter and easier to open. The decrease in hatch weight is proportional to the cosine of the angle of the hatch opening. At zero angle or closed position, the full weight of the hatch is on the worker. At a 30-degree pop-up angle, 13 percent of the hatch weight has been reduced for the worker, where the effective hatch weight to the worker is then reduced to zero as the hatch angle approaches a 90-degree opening.
In the full open position, the hatch has been rotated to an obtuse angle where the hatch typically rests on a locking arm or other mechanism that functions to catch and hold the hatch up to prevent it from rotating too far open, to fall on the ground beside the utility vault. Thus, once the vault cover is rotated beyond the perpendicular point, the locking arm or other mechanism may support the hatch and prevent it from rotating to a position that is 180 degrees from the closed position and falling on the ground beside the utility vault. This occurrence is undesired because from this position, typically, a forklift or other heavy machinery is necessary to lift up the heavy utility vault cover hatch and rotate it back 180 degrees in order to close the hatch. On the other hand, with the current design, one worker can open and close the hatch without the use of a forklift or other heavy machinery.
There have been lift mechanisms or pop-up mechanisms in the prior art to perform this task; however, all prior art pop-up mechanisms suffer from a problem that occurs when the torque member or tension member used to supply the pop-up force wears, weakens, or warps to yield a decreased pop-up distance. Because of the extremely sturdy designs required of traffic-rated utility vault covers that must withstand the pounding abuse from vehicular traffic passing across the top of the utility vault cover, utility vault covers of this sort are extremely heavy. This extreme weight causes continuous heavy pressure from the heavy hatch on the pop-up mechanism, which causes the torque member or tension member to wear, weaken, or distort from its original position. This results in a reduction of torque or upward force, thereby causing a decrease in pop-up distance of the hatch upon release of the locking and/or latching mechanisms. Once the pop-up distance falls to 7 inches or less, it becomes much more difficult to get hold of the heavy hatch and rotate it all the way over for the locking arms to catch. As the pop-up gap of the lift mechanism gets smaller, the hatch becomes much more heavy to rotate upward. In extreme cases, the torque member or tension member cracks from the continuous pressure and breaks into pieces yielding total failure with zero pop-up distance.
A traffic-rated utility vault and a utility vault cover must typically last at least 10 years or more, while the torque member or tension member used to supply the pop-up force for traffic-rated utility vault covers typically loses substantial pop-up torque or force after only about one year. A loss of pop-up distance is the result of the weakening or wearing or distorting of the torque member or tension member used to supply the pop-up torque or force to the pop-up mechanism. For example, a new utility vault cover with pop-up distance initially set at 12 inches typically incurs a reduction in pop-up distance to about 6 inches after only one year of service. This is a 50 percent loss of pop-up distance after only 10 percent of the utility vault's lifespan. The task of opening the hatch of the utility vault becomes much harder as the pop-up distance decreases. Back injuries can occur more frequently when this happens. The result is that workers and utility crews have a much more difficult time opening the hatches of traffic-rated utility vault covers after they are just a few years old and this difficulty remains and worsens throughout the remainder of the vault's lifespan.
To combat the loss of pop-up distance problem, the applicant has devised an adjustable torsion lift system with one-way bias that does not push back onto the torque member or tension member as the hatch is opened or closed beyond the pop-up distance. This design yields much less stress on the torque member or tension member, thereby reducing wear, weakening, and warpage of the torsion device or spring. This design is a substantial improvement over the decades old industry standard of applying continuous torsion assisted lift by eliminating 100% of reverse stress on the torsion member.
To combat the loss of pop-up distance problem, the applicant has devised an adjustable torsion lift system with one-way bias that provides the ability to quickly and easily set the initial pop-up distance of the traffic-rated utility vault cover to any desired distance during the installation of the traffic-rated utility vault cover or the utility vault.
To combat the loss of pop-up distance problem, the applicant has devised an adjustable torsion lift system with one-way bias that provides the ability to set and reset the pop-up distance of the traffic-rated utility vault cover to the desired distance and to keep it at that distance for the entire lifespan of the utility vault cover, even after wear, weakening, or warpage of the torque member or tension member.
To combat the loss of pop-up distance problem, the applicant has devised an adjustable torsion lift system with one-way bias that provides the ability to “retention” or add more tension to the torque member or tension member after the torque member or tension member incurs wear, weakening, or warpage, without removing the adjustable torsion lift system with one-way bias from the utility vault cover or replacing components thereof, thereby providing the ability to keep the same pop-up distance for the entire lifespan of the traffic-rated utility vault cover without replacing the original torque member or tension member.